Assistant to the President for Counterterrorism and Homeland Security John Brennan (left) and Press Secretary Robert Gibbs (right) give a briefing about the security alert issued after suspicious packages were found on cargo planes bound for the United States.

All churches, synagogues, and mosques in the Chicago area are being urged to be vigilant for any unsolicited or unexpected packages, especially those originating from overseas locations.

The Anti-Defamation League has further alerted synagogues across the United States after learning from law enforcement sources of “a reported threat to Jewish institutions in the form of packages mailed from overseas, particularly Great Britain, Yemen and Saudi Arabia.”

“In light of the reported threat, the League has sent out a notice to U.S. Jewish communal institutions across the country to increase mailroom security and to contact law enforcement immediately if they see anything suspicious,” the group reported Friday.

Before the announcement, two “suspicious packages” bound for the United States were found to contain explosives.

The packages, which were en route to two places of Jewish worship in Chicago, had been located in Dubai and the East Midlands Airport in the United Kingdom. Both were found to have originated in Yemen.

According to the White House Press Secretary Robert Gibbs, President Obama was alerted of the “credible terrorist threat” at 10:35 p.m. Thursday night. Shortly after, a number of federal agencies were informed of the threat and mobilized to action.

“I directed the Department of Homeland Security and all our law enforcement and intelligence agencies to take whatever steps are necessary to protect our citizens from this type of attack,” reported President Obama in an statement delivered late Friday afternoon.

Adding to that, Assistant to the President for Homeland Security and Counterterrorism John Brennan told reporters that the FBI, Department of Homeland Security and other domestic agencies “have reached out to the appropriate private-sector entities as well as organizations to ensure that any other potential targets of such attacks are alerted.”

“So we’re working very closely with state and local officials,” he added.

Presently, a forensic analysis of the two packages is underway as federal investigators look into possible suspects. Until the analysis is completed, DHS has declined from speculating on the potential extent of damage the packages could have caused.

What can be said, however, is that the devices “intended to do harm.”

“We are working closely with [the Yemeni government] and we are going to get to the bottom of this plot,” Brennan reported.

Religious institutions have been encouraged to contact law enforcement immediately if they see anything suspicious.